[NFC] Replace uses of Type::getPointerTo Replace some uses of `Type::getPointerTo` via 2 ways * Remove entirely if it's only used to support an unnecessary bitcast (remove the bitcast as well). * Replace with `PointerType::get`/`PointerType::getUnqual` NFC opaque pointer clean-up effort. GitOrigin-RevId: 204883623ebd194669fc54435222e5bfb245b011